This invention relates to a method for treating textile fibers and to the modified fibers obtained thereby. More specifically this invention relates to a process for durably affixing a polydiorganosiloxane to surface of a condensation-polymer fiber or a cellulosic fiber without using a curing component for crosslinking the polydiorganosiloxane.
It has long been known to apply a curable organopolysiloxane composition to a fabric or fiber and to subsequently cure the applied organopolysiloxane by the action of a second curing component to produce a fiber or fabric that is surrounded by, i.e. encased in, a sheath of the cured organopolysiloxane composition.
However, a two-component curable composition has certain deficiencies. For example, said curable compositions must often be prepared, shipped, and stored in two or more non-curing packages, which are mixed shortly before the intended time of use, in order, to avoid premature curing of the composition. This requirement is costly and time consuming. Furthermore, relatively large amounts of a two-component curable composition must be added to a fabric or fiber in order to provide sufficient integrity for the cured composition to resist mechanical removal, such as by abrasion.
Another method for modifying the surface of a synthetic material is disclosed by Lipowitz in U.S. application Ser. No. 689,395, titled "Non-Crosslinked-Silicone-Coated Thermoplastic and Process Therefor," filed May 24, 1976 and assigned to the assignee of this invention. Therein a non-crosslinked silicone is durably affixed to a surface of a thermoplastic by applying a non-crosslinking silicone to the thermoplastic at a temperature greater than the glass-transition temperature but less than the melting temperature of the thermoplastic. However, the resulting silicone treatment is durable only at temperatures below said glass-transition temperature.
Gowdy, et al, U.S. Pat. No. 3,535,145 claims a process of applying certain mercaptohydrocarbon-substituted organosilicon compounds to the surface of a vinylic polymer and applying heat or actinic radiation energy to the surface of said vinylic polymer to irreversibly attach said organosilicon compound to said vinylic polymer. Gowdy, et al. teaches that only vinylic polymers may be altered by the application of an organosilicon compound containing at least one mercaptohydrocarbon radical.
We have found that certain polydiorganosiloxane fluids comprising saturated hydrocarbon radicals bearing mercaptan groups may be durably affixed to non-vinylic polymer fibers.